Combination retort and hearth for stokers



Jan. 8, 1946. T. c;- cHEAsLEY COMBINATION RETORT AND HEARTH FOR STOKERS original Filed .Juie 19, 1940 Patented Jan. 8, 1946 COMBINATION RETORT AND HEARTH FOR` sToxERs Thomas C. Cheasley, KansasV City, Mo.

Original application June 19, 1940, Serial No. 341,272. Divided and this application January 16, 1943, Serial No. 472,580

8 Claims.

This invention relates to a combination retort and hearth particularly adapted for use in stoker fed boilers and is a division of my copending application filed June 19, 1940, Serial No. 341,272, now Patent Number 2,320,410.

Boilers are usually constructed with Water legs forming side Walls of the fire-box. Consequently dirt, scale and foreign matter in the boiler water settle to the bottom of the water legs andcollect upon the mud rings so that circulation in that portion of the water legs is substantially blocked .by the settled material. When such boilers are equipped for stoker feed of the fuel the hearth of the Stoker mechanism is located adjacent themud ring vportion of the water legs, consequently the intense heat of the fuel plays directly thereon with the result that the inner walls of the water legs are excessively heated and are apt to give way under boiler pressure.

It is, therefore, a principal object of the present invention to provide means in association with the hearth of a Stoker mechanism for protecting the lower portion of the water legs from direct contact with the inner walls thereof and thereby prevent overheating thereof.

Other objects of the invention are to provide the hearth of the stoker mechanism with a watercooled curb to form a protection for mud ring portions of the water legs and to provide means for effecting circulation of a cooling liquid through the hearth and particularly the portion thereof forming the curb thereof.

It is a further object of the invention to provide a boiler with means in association with the water-cooled hearth and retort to effect positive circulation at the mud ring portions of the water legs of the boiler.

In accomplishing these and other objects of th'e invention, I have provided improved structure, the preferred forms of which are illustrated in the accompanying drawing, wherein:

Fig. 1 is a Vertical section through the lower portion of the fire-box of a boiler equipped With a stoker apparatus and hearth embodying the features of the present invention.

Fig. 2 is a modified form of the invention sh'owing the water legs provided with extensions which cooperate with water jacket extensions of a retort for forming a water-cooled hearth through which water from the lower portions of the water legs is circulated to control temperature of the hearth and prevent over-heating of the lower portions of the fire-box walls,

Referring more in detail to the drawing:

f I designates an ordinary re tube boilerhavlng a fire-box 2, the walls of which comprise inner and outer sheets 3 and 4 spaced apart to providey water legs 5 for the circulation of boiler water around the fire-box, the lower edges of the sheets: being connected to form a mud ring 6 that is sup-A ported upon the boiler foundation 1 which forms the walls of an ash-pit 8.

The front of the fire-box is provided with the usual door opening 9 opening into the lire-box.

Extending through the front of the foundation 1 'are air and fuel ducts I0 and I I of a stoker apparatus which' ducts are connected with a feed hopper and fan (not shown). The airduct I0 discharges directly into the ash-pit and supplies f combustion supporting air for the fuel delivered through the duct II. The duct II projects into the ash-pit and terminates in an upwardly di- I rected outlet I2Y forming the lower section of a retort and having a flange I3 for seating the upper Section I4. The upper portion of the outlet I2 cooperates with the upwardly diverging wall I5 of the retort to provide a substantially conical shaped retort chamber I6. The wall I5 terminates near the horizontal plane of the mud ring 6 in a laterally extending plate portion I1 which forms the fuel supporting portion of a hearth'.

In the illustrated instance, the outer marginal portion of the plate I1 terminates short of the water legs of the lire-box and connected therewith is an upwardly extending curbing flange I9 curving into an outwardly directed rim portion 20 which substantially closes the space around the hearth and prevents burning fuel and ashes carried on the plate I1 from contacting the inner surfaces of the water legs of the boiler, the flange I9 being of suicient height to extend upwardly of the water leg so that it is above that portion of the water-leg in which th'e mud and sediment usually collect.

Mounted upon the plate portion I1 and ary ranged circumferentially of the retort chamber I6 is a tuyre 2 I. The tuyre includes a ring having an inner Wall portion 22 provided with a plurality of air discharge openings 23. The upper part ofthe wall 22 rounds outwardly and downwardly, as at 24, and connects with an outer wall portion 25 provided at its base with a laterally extending flange 26 seated upon the plate portion I6 of th'e hearth. The tuyre thus forms an annular manifold chamberV 21 having connection with the ash-pit 8, later described. The Wall portion 25 of the tuyre may also have a series of air discharge openings 28 which are directed toward the fuel bed which is supported upon the plate I1.

Fuel is delivered from the hopper (not shown) of the stoker through ther duct Il by a screw conthe rate of feed of fuel and amount-'oran' deliv-1 Yered are in proper proportions using a good grade of Stoker coal, there maybe vsatisfactorily maintained but anystoppage of the fuel feed or with too large amount of air, the fire may burn down into the retort and below the level at which the l:airAent'ers.through :the Lvtuyre with the -result thatther metal wall.y of 'the tuyreis excessively `Vheated and' soon 1 deteriorates. With certain types fofl coal,` ther-fuel cakes intoi a; solid mass wwhich arches over the :tuyre A so. thatfrthe: re v=cannot pass' therethroughvv withA the .-'result vrthat the fire burns on the bottomside and around the yedgesi-andfinto:the retort, causing.- damage to the retort, ...'YA-nother disadvantagexis that the #hearthy :becomes excessivelyjfhot .and causes the clinkerwash of theiso-.calledfusioncoals toadhere thereto`-and"ma-ke `it diiicultto. remove. Y

.'Iovovercome thesef` and otheri difficultiesy of present 'stoker mechanisms, I provide the retort Vwith awater :jacket 3l)l throughwhich-'water` is 1,-Icirculatedito maintain a predetermined-maxitemperature of the retort and; prevent in- :juryfthereto .incase the Are 'shouldburn therein. IihaVe-urtheri-provided the plate yI.'l-,andthe curbing 'lQ-r which protect the mud ringportion,

'zof 4the water'legs with water fjackets 3| and-32 which may be formed as continuations of. the 11a/ateiy jacket "30, thereby preventingfthe plate 14 'IH-and curbingi9.from::lrieating,to thefpoint l'wherethe. 'clinker' will vtenda to stick!V thereto.

F34*extending*substantially 'parallel with the -re- :.toi-t"wall.f i to form 'a=waterfpassageway13E-therevz'llr'etween. Theupperportion ofthe wall-.34:curyes "outwardly ein` 'downwardlyv spaced relation,` with ltheiplate' ll, asat13,vnto a'vsubstantiallyfhorizontal plate portion 3l so as tonformV aafwaterf.

circulating space'S under the platerv I l andffwhich has connection with the-'water 'circula-ting; space v'The plateportion `3l-xfternfiinatesadjacent-the "innere-faces. of theifire legs, asatgiandfxconnets sav-ith :therimiiby a wallul@ to ferm la :watercirnculatingg space *4 l' .surrounding the: curbing .1.19, fwhichlzspace. is connected .withffthe @circulating :iispacef 38. fWater is 'admittedY to'fthe: lowenzportionlof. thecirculatingspace tith'roughanfinlet .lpip'elllland is 'discharged throughzan'ioutlet: pipe 4 'fwhich-` isishowni asv 1connected1w-ithethef water 'i'circ'ulating spac'ei35.

.-rmzprdea-tofaumit. air. immane.:ashpitsfwane Y .manifoldchamberz ofazvthe ztuyre;Y therlvupper 'and "i lower plate portions l1 and 33 are connected by tubular ducts 44 so that the combustion supporting air is conveyed through the water space and preheated by the water circulating through the respective passageways. If it is desired to provide a live plate for the hearth, theY plate portions Il and 31 are, connectedl bytubularrducts 45 so ...that air" is admitted intoltheg'fuelbed Supported by the hearth.

. In order to providea seal between the water "'"legs and wall 40, the wall 40 is ,slightly spaced 'afrom ythe,sinner,plates. 3 of the water legs to 'raccommodate a sealing material 46 that is insertedtherein. l

l"With the structure thus described, the wall I5 of the retort yis kept in cool condition and no air vis.-,admittedfthereinto so that the re is maintainedfaboveathe .dead plate and in position to heatthewater legs of the boiler, However, the water-cooled curbing portions of the hearth preventi overheatingfof the mud ring. portions.- ofthe A-=.waiterflegs l; vGases' 'fromathe fuel arey evolved; in. the. 'retort ,and .lmixed with, the `combustion .supporting Aair admitted to the tuyre.throughlthetubulariducts In!y thegformn of; the@ invention shown fina-Fig.12,

f Vthe-:water jacket 4l' fof;1theretort. terminates adfiacent the ilangeu '.ofthe tuyre. 49.andf, abuts inwardly extending. horizontal extensions-:5050i -the vwater legs f5 I 1 `,of the; bollen, the,v extensions :cooperating Awith the" retort to form a 1fuel.| sup- :fporting hearth :352. cooled by water circulatedl in fthe, legssof the fboiler. L The extensions; v5E! :z are @connected with; the.; :water-.cooled spacer offthe retort bypipes 53. Thusfthe :boilerywater-,ltends @tot circulate; r,inv `the/lower portion::.of the.: water '.,legsgtq preventsettlng 1 of mud-'1 andv thefliketon nthe mudY ring oflthe zboiler. i With this,A :arrangement the :curbingof the; hearth mayrbexomtted 1sincethe inneriwa11=of therme-box doesnotoverheat because foreign`V materials do. notg settle.; out

in the Water legs of thedooiler. y -ilrom the foregoing itzis` obvious :that v.I have :providedr'protection fof L the retort of aithe stoker apparatus so asVv tto r: avoidl overheating: thereof, `:thereby.providing a-retortgiof longer life-:and-more ecient operation. It is also obvious-that I have provided a water-.cooled hear-thlwhichisequipped fwithfl avvwater-.cooled -1 curbing to Mpreventfloverheating'. ofiithednner wallsfof the.r .waterflegs'of a l boiler.

fhearth..;are :controlled vsoaasato .avoid:sticking of znl'inkers-tofatherlegs of thezboiler and metalz'sur- ..facesf of the hearth. with f :the .f result thatl :these Corisequentlyi'A the; temperatures :Y ofifthe clinkers may be :readily: removedf-i While: it fris desirable i: toprovide a'vcontinuouslfiowi of water stliroughthe --coolinge jacketsatherefis fnoe-losszfof efficiency or increase. .in-.sexpense' of operationias ythemheated. .fwaterg may-be used' in .therl yboilerufor increasingzcirculationtherein,

l`MIK/That I cla-im :andidesire=to. securef1bysLetters fBatent: is:

, 1. In Combination with maare-borrar atelier havingawall's thereof formed -byrspacedsinnerv and Y :outer-.3 sheets :connected ati their-f lower edges to form water legs, a stoker mechanism for supplying fuel to the fire-box including a hearth adapted to support burning fuel, and a watercooled curbing surrounding the hearth projecting upwardly alongside inner faces of said inner sheets for preventing overheating of the inner sheets of the fire-box adjacent said hearth.

2. In combination with the fire-box of a boiler having water legs, a retort supported1 in the rebox, and a jacket surrounding the retort and forming a space for circulation of a cooling medium, said water jacket including an upwardly extending curbing portion lapping the water legs for protecting the legs of the boiler from direct heat resulting from combustion of fuel delivered through said retort.

3. A mechanism of the character described including, a retort, a hearth for receiving fuel thereon from the retort, a water jacket underlying the hearth, a tuyre encircling the retort, and a curbing for the hearth having a passageway connected with said water jacket, said curbing having a height substantially corresponding to height of the tuyre.

4. In combination with a fire box of a boiler having Water legs, a retort supported in the nre box, a hearth for receiving fuel thereon from the retort, a water jacket underlying the hearth, a

tuyre encircling the retort and extending above' the hearth, and a curbing for the hearth extending upwardly of the water legs substantially the height of the tuyre and having Ia passageway connected with the Water jacket.

5. A combination retort and hearth for a rebox having Water legs forming the side walls of said fire-box including a retort, including a hearth for receiving fuel from the retort, and a hearth for receiving fuel from the retort, a water jacket underlying the hearth, and a curbing extending around the hearth and overlapping portions of the water legs adjacent thehearth, said curbing having a passageway connected with the water jacket.

7. A combination retort and hearth for a rebox having Water legs forming the side walls of 4 said re-box including a retort, including a hearth for receiving fuel from the retort, a water jacket underlying the hearth and surrounding the retort, andra curbing extending around the hearth and overlapping portions of the water legs adjacent the hearth, said curbing having a water passageway and connected with the water jacket.

8. In combination with a fire-box of va boiler having walls thereof formed by spaced inner and outer sheets to provide water legs and a mud ring connecting said inner and outer sheets, a stoker mechanism for supplying fuel tothe lirebox including a retort, a hearth surrounding the retort, means cooperating with the hearth and said retort to provide a passageway for circulation of water, a tuyre surrounding the retort and extending above the hearth, water circulating means surrounding the hearth and located within the fire-box for providing water circulation in cooling relation with the portion of the inner sheets above the mud ring.

THOMAS C. CHEASLEY. 

